Key
y stone species,
p
, MPAs and the ecosystem
y
approach
pp
Important benthic ecosystem engineers as a tool to implement the
ecosystem approach to management
Marijn Rabaut, Ulrike Braeckman and Magda Vincx
22nd of March 2011, Leuven, Belgium
Maes et al., 2005
Rabaut et al., 2009
8
Sandbanks are elevated, elongated, rounded or irregular topographic features,
permanently submerged and predominantly surrounded by deeper water
water. They
consist mainly of sandy sediments, but larger grain sizes, including boulders
and cobbles, or smaller grain sizes including mud may also be present on a
sandbank Banks where sandy sediments occur in a layer over hard substrata
sandbank.
are classed as sandbanks if the associated biota are dependent on the sand
rather than on the underlying hard substrata.
Abra alba
Macoma balthica
Nephtys cirrosa
Ophelia limacina
Degraer et al, 2009
Degraer et al, 2009
Gravel beds
Lanice conchilega aggregations
Reefs can be either biogenic concretions or of geogenic origin. They are hard
compact substrata on solid and soft bottoms, which arise from the sea floor in
th sublittoral
the
blitt l and
d litt
littorall zone. R
Reefs
f may supportt a zonation
ti off b
benthic
thi
communities of algae and animal species as well as concretions and
corallogenic concretions.
Degraer et al, 2009
Degraer et al, 2009
Multi-level g
government
Flemish Region on land:
•nature conservation
•tourism
•ports…
Federal state at sea:
•nature conservation
•protection
protection of the marine
environment
•offshore windmill parks
•shipping
•military…
ilit
Flemish Region at sea:
•fishing
•dredging...
Province of West-Flanders
Coastal municipalities
Federal
F
d l state
t t on land:
l d
•contingency planning…
Taken from Prof. Dr. A. Cliquet
Biodiversity
Ecosystem
Ecosystem functioning
Habitat H
bi
complexity
Ecosystem engineers
Ecosystem engineers
Interview Daniel Pauly – (c) Sea the truth
“The
The Southern North Sea is not in natural state
state, the bottom of the North Sea
was once covered with animals, solidifying the seafloor”
Biological mixing influence on benthic fluxes and bi t b ti
bioturbation
Bioturbator ‐ Abra alba
Burrowing bivalve
Efficient bioturbator: organic matter redistribution
A. alba densities are important to maintain bioturbation
A. alba does not draw oxygen deep into sediment
A alba does not draw oxygen deep into sediment
siphons
Feeding pits
Braeckman et al, 2010
Pseudofaeces
Biological mixing influence on benthic fluxes
g
g
Bio‐irrigator ‐ Lanice conchilega
Tube‐dwelling polychaete
Bio‐irrigator: Oxygen deep in sediment
Stimulates mineralization processes (e.g. denitrification)
L. conchilega densities are important for mineralization
L conchilega densities are important for mineralization
Ferric
hydroxides
L. conchilega in
microcosm
Braeckman et al, 2010
© Studio Lore (L. Rabaut)
Rabaut et al., 2010
© Peter Auster
Rabaut et al.,2008
Habitat modification
Interactions
“REEFS ARE
THREATENING
OUR COAST”
BMM-Van Lancker
Multibeam imagery RV Belgica EM3002
(c) Kerckhof
39
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